Nutrition and health value of sialic acid in early life

Sialic acid (SA) is a naturally occurring derivative of nine-carbon monosaccharides that are typically present as oligosaccharides, glycoproteins, or glycolipids in the blood during pregnancy and in breast milk. Hepatic synthesis of SA occurs from the fetal period to 6 months after birth; therefore, exogenous SA is essential for early life growth and development. This review examines the nutritional requirements for various forms of SA in early life, considering its content in the maternal serum, breast milk, and supplementary infant foods. Additionally, it examines the synthesis and metabolism of SA, its roles in the brain and intestinal development, immune system maturation, and its efficacy in preventing and managing preterm birth and related conditions. Finally, it highlights crucial research in SA nutrition in early life to provide a scientific basis for the use of SA in infant formulas, maternal food, and medical settings.